Career over and rightly so? That's very very harsh indeed. He's not a surgeon, he didn't cost us a life, just some pride and another cup in the trophy cabinet.
He most certainly isn't the first keeper to throw the ball to the opposition - in fact every keeper will have done that. It was very very unfortunate that it just happened to happen on that night. And it's more than likely that adversely affected him - leading to another error.
He has gone on record numerous times rightly blaming himself for us not winning the cup (I agree, I think we certainly could have). However just because he's not a world class keeper shouldn't mean his career is over.